Abrasive member

ABSTRACT

A grinding and polishing device in which particles of abrasive material project outwardly from a working surface characterized by having a multiplicity of interspaced rounded protuberances and depressions which are joined together to form smoothly rounded peaks and valleys extending over substantially the entire working surface. The protuberances formed on the working surface are wearable under operating conditions so that during grinding or polishing operations, fresh abrasive particles disposed along the lower regions of the sloping surfaces of the protuberances will be continually exposed to the work.

Unite States Patent [191 Greenspan 1 Mar.4, 1975 1 ABRASIVE MEMBER [76] Inventor: Harold Jack Greenspan, 5334 Holt Aver, Los Angeles, Calif. 90056 [22] Filed: Sept. 14, 1973 [21] Appl. N0.: 397,371

[52] US. Cl 51/209 R, 51/395, 51/204 [51] Int. Cl B24d 3/08, B24d 7/18 [58] Field of Search 51/209 R, 209 DL, 395, 51/396, 204

[56] References Cited UNITED STATES PATENTS 922,382 5/1909 Brenizer 51/209 R X 2,020,117 11/1935 Johnston 51/209 R 2,246,362 6/1941 Kehoe et a1 51/209 R 3,246,430 4/1966 Hurst 51/402 3,259,959 7/1966 Tobey 51/209 R X 3,420.007 1/1966 Kolesh 51/209 R 3,495,362 2/1970 Hillenbrand 51/395 Primary Examiner-A1 Lawrence Smith Assistant Examiner-K. J. Ramsey Attorney, Agent, or FirmWhanrl & McManigal [57] ABSTRACT A grinding and polishing device in which particles of abrasive material project outwardly from a working surface characterized by having a multiplicity of interspaced rounded protuberances and depressions which are joined together to form smoothly rounded peaks and valleys extending over substantially the entire working surface.

The protuberances formed on the working surface are wearable under operating conditions so that during grinding or polishing operations, fresh abrasive particles disposed along the lower regions of the sloping surfaces of the protuberances will be continually exposed to the work.

4 Claims, 5 Drawing Figures ABRASIVE MEMBER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to abrasive devices and more particularly to radial diamond charged wheels for cutting, grinding and polishing rela tively hard materials of the type encountered in lapidary work.

2. Discussion of the Prior Art Numerous types of abrasive devices are found in the prior art and diamond charged abrasive elements have long been used. Typically, prior art abrasivedevices are made by rolling abrasive particles such as diamond dust into metallic discs or by bonding the particles onto the working surface of the discs with various types of binding and ceme'ntitious materials.

A common fault of many prior art abrasive devices is that in use, particularly on relatively hard workpieces, the abrasive surfaces soon wear smooth and become highly inefficient. This, of course, is caused by a wearing down of the cutting edges of the abrasive grains which project outwardly from the working surface. Once these jagged cutting edges of the particles wear smooth, the efficiency of the device rapidly diminishes.

The novel device of the present invention avoids the drawbacks of the prior art devices by providing an abrasive carrying working surface of highly unique configuration which is wearable under operating conditions in a manner so as to continually present to the workpiece fresh abrasive particles.

Because new abrasive particles are continually presented to the workpiece as some of the particles wear smooth, the cutting efficiency of the device remains high even after extended periods of use.

Additionally, because of the novel surface configuration ofthe device, many of the abrasive particles which, during use, have been worn smooth and have become loosened, are reoriented and re-embedded into flattened plateaus which are continually being formed on the working surface during the grinding operation. This feature of the invention permits maximum use to be made of the relatively expensive abrasive materials and further enhances the operational efficiency of the device.

The following prior art patents describe the most pertinent art known to applicant and serve to clearly indicate the high degree of novelty of applicants invention as described and claimed herein:

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved grinding, cutting, polishing and lapping member of the type in which particles of abrasive material such as diamonds are at least partially embedded or encapsulated into a working surface characterized by having a multiplicity of interspaced rounded protuberances and dished-out depressions which are joined together to form smoothly rounded peaks and valleys extending over substantially the entire working surface.

It is another object of the invention to provide a grinding member of the type described in the previous paragraph in which the working; surface is wearable under operating conditions so that during grinding or polishing operations the protuberances or peaks of the working surface will tend to uniformly wear down, thereby continually exposing to the workpiece the fresh abrasive particles which project outwardly from the lower regions of the sloping surfaces of the protuberances.

It is another object of the invention to provide a grinding member of the aforementioned character in which the working surface is formed of a soft, comparatively ductile embossed metal sheet material such as copper or steel which is affixed to a solid base supporting member.

It is still another object of the invention to provide a grinding member as described in. the preceding paragraphs in which the abrasive particles are held in position on the working surface by a metallic coating such as nickel uniformly deposited upon the working surface.

It is a further object of the invention to provide a grinding and polishing member of the class described in which the member is generally cylindrically shaped and is provided with an axial bore for mounting the member onto a rotatable spindle.

It is still another object of the invention to provide a grinding member as described in the previous paragraph in which the abrasive particles are located uniformly along the sloping surfaces of the peaks and valleys of the working surface and project outwardly therefrom so that under operating conditions, as the peaks wear down, not only will the fresh particles along the sloping sides of the peaks be exposed to the work, but also the abrasive particles which have previously come into engagement with the work will tend to be reembedded into the flats formed on the tops of the protuberances, thereby making maximum use of the expensive abrasive particles and enhancing the grinding or cutting operations.

It is a further object of the invention to provide a novel grinding member of the class described which has superior operating characteristics and yet may be expeditiously and inexpensively manufactured.

In summary, these and other objects of the invention are achieved by a novel abrasive member having a working surface provided with a multiplicity of interspaced convex protuberances and concave depressions blended together so as to form smoothly rounded peaks and valleys and a multiplicity of abrasive particles fixedly attached to the working surface so that at least portions of the particles extend outwardly from the surfaces of the protuberances and depressions formed on the working surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of abrasive member of the present invention shown here in the form of a radial grinding and polishing wheel or disc adapted to be mounted upon a rotatable spindle.

FIG. 2 is a view taken along lines 2-2 of FIG. 1 illustrating the cylindrical shape of the device and showing the manner in which the embossed sheet metal working surface is arranged on the face of the disc.

FIG. 3 is an enlarged fragmentary view of the working surface showing the interspaced protuberances and depressions as they appear looking directly at the face of the disc.

FIG. 4 is a greatly enlarged cross-sectional view taken along lines 44 of FIG. 3.

FIG. 5 is a view similar to FIG. 4 showing the appearance of the device after use in grinding or polishing operations.

DESCRIPTION OF ONE FORM OF THE INVENTION Referring to the drawings, FIG. 1 shows the abrasive member of the invention in the form of a radial grinding, cutting, polishing and lapping wheel or disc 12 of the type frequently used for lapidary work and the like. Disc 12 is generally cylindrically shaped, having a face 14 and an annular flange 16. An axial bore 18 is provided for mounting the disc onto the rotatable spindle of a handor power-operated driving means (not shown).

As best seen in FIGS. 3 and 4, disc 12 has a working surface 20 provided with a multiplicity of interspaced convex protuberances 22 and concave depressions 24 blended together so as to form smoothly rounded peaks and valleys or dished-out portions.

A multiplicity of abrasive particles 26 are fixedly secured to working surface 20 so that at least portions of each particle or grain extend outwardly from the sloping surfaces of protuberances 22 and depressions 24.

Although various types of abrasive materials can be used, depending upon the end use to be made of the device, diamond, boron nitride and aluminum oxide have been found satisfactory for wheels used in lapidary endeavors.

The working surface of the device is constructed of a soft, but tough and comparatively ductile metal, such as steel or copper, which is wearable under operating conditions, i.e., is somewhat softer than the material to be worked. When a material such as copper is used, the wheel wears relatively fast resulting in a shorter life, but providing a faster cutting action. When, on the other hand, steel is used, the wheel wears more slowly, while at the same time, providing a slower cutting action than does a copper wheel. Selection of other types of metals would, of course, provide varying degrees of wear and cutting speeds.

Referring now particularly to FIG. 4, there is provided in the embodiment shown a particle bonding material 28 which forms a part of the working surface 20 and serves to hold the abrasive particles in place on the working surface. Desirably, the abrasive particles are uniformly spaced apart over the entire working surface and are embedded or encapsulated in the bonding material with at least a portion of their jagged or cutting edges projecting outwardly from the sloping surfaces of the peaks and valleys.

As illustrated in FIGS. 2 and 4, the wheel of this form of the invention is constructed from two parts; an embossed metal sheet member 30 and a cylindrically shaped solid member generally designated by the numeral 32. In the construction shown, member 30 is formed with the spaced apart convex protuberances and concave depressions, the latter having flat portions 34 formed on the underside of the part. These flat portions facilitate joining the parts together by any suitable bonding means such as soldering or cementing.

For certain applications, the abrasive member is constructed from a single cylindrically shaped metal piece and the peaks and valleys are formed directly on the face of the part. The construction shown in the drawings, however, has proved quite satisfactory for most uses and is somewhat less expensive to fabricate. When the solid construction is used, it is also preferable in certain instances to roll or otherwise pressurally embed the abrasive particles directly into the surface of the part without using any type of coating or bonding material.

When a particle bonding material is used, either with the single or two-piece construction, good results have been obtained by using a metallic bonding material such as nickel which can be deposited onto the surface of the part by vapor deposition or other plating techniques. Such a coating effectively encapsulates the abrasive particles and securely holds them in position on the working surface. For certain applications, various adhesive materials such as epoxy resins and the like can also be used as a bonding material.

It is to be understood that although a radial wheel abrasive member is shown in the drawings, variously configured members can be constructed in accordance with the teachings of the present invention. For example, the abrasive members may be conical, parabolic or drum-shaped and may be constructed using an embossed sheet metal working surface or they may be constructed as a single piece having an appropriately formed working surface.

OPERATION With the radial wheel construction shown in the drawings, grinding or polishing operations are accomplished by pressing a workpiece, such as a gem, stone, or the like, against the working surface 14 of a rapidly rotating abrasive member 12. Initially, the workpiece engages the abrasive particles 26 projecting from the uppermost portions of the peaks or protuberances 22. As the particles wear down the workpiece will engage the metal of the working surface. Because the metal working surface is softer than the workpiece, it will tend to wear down as shown in FIG. 5. As this occurs, the fresh abrasive particles designated as 26a in FIG. 5 which are located on the lower portions of the sloping side walls of the protuberances 22 will come into engagement with the workpiece. In this way, as the uppermost abrasive particles wear smooth and lose their cutting ability, new particles continually come into engagement with the Work, thereby maintaining a high degree of cutting efficiency.

Because the working surface is made up of smoothly rounded protuberances and valleys, undesirable chattering, vibration and grabbing is eliminated during the grinding and polishing operations. Also because of the unique working surface configuration, the abrasive particles which have been worn smooth and have been dislodged (identified as 26b in FIG. 5) tend to move into the flattened areas 36 and become re-embedded into the working surface. These particles further enhance the cutting efficiency of the wheel and, along with the fresh particles 26a which are exposed, provide a continually renewed abrasive working surface.

I claim:

1. An abrasive member comprising:

a. a generally cylindrically shaped rigid'disc having an axial bore for mounting it onto a rotatable spindle;

b. a working surface provided with a multiplicity of interspaced convex protuberances and concave depressions blended together so as to form smoothly rounded peaks and valleys extending over substantially the entire working surface, said working surface comprising an embossed metal sheet material affixed to said rigid disc, said rigid disc providing a substantially continuous planar surface for supportable contact with said metal sheet; and

c. a multiplicity of abrasive particles fixedly positioned relative to said working surface so that at least portions thereof extend outwardly from the surfaces of the protuberances and depressions formed on said working surface.

2. An abrasive member comprising:

a. a rigid support member;

b. a working surface on said support member provided with a multiplicity of interspaced convex protuberances and concave depressions blended together so as to form smoothly rounded peaks and valleys extending over substantially the entire working surface, said working surface comprising a metal sheet material affixed to said support member, said support member providing a substantially continuous planar surface for supportable contact with said metal sheet; and

c. a multiplicity of abrasive particles fixedly positioned relative to said working surface so that at least portions thereof extend outwardly from the surfaces of the protuberances and depressions formed on said working surface.

3. The abrasive member as defined in claim 2 in which said working surface is uniformly covered with a particle bonding material and said abrasive particles are embedded in said bonding material uniformly along the surfaces of the peaks and valleys of said working surface.

4. The abrasive member as defined in claim 3 in which said metal sheet material is a soft, comparatively ductile metal which is wearable under operating conditions and said bonding material comprises a nickel coating uniformly covering said sheet material. 

1. An abrasive member comprising: a. a generally cylindrically shaped rigid disc having an axial bore for mounting it onto a rotatable spindle; b. a working surface provided with a multiplicity of interspaced convex protuberances and concave depressions blended together so as to form smoothly rounded peaks and valleys extending over substantially the entire working surface, said working surface comprising an embossed metal sheet material affixed to said rigid disc, said rigid disc providing a substantially continuous planar surface for supportable contact with said metal sheet; and c. a multiplicity of abrasive particles fixedly positioned relative to said working surface so that at least portions thereof extend outwardly from the surfaces of the protuberances and depressions formed on said working surface.
 2. An abrasive member comprising: a. a rigid support member; b. a working surface on said support member provided with a multiplicity of interspaced convex protuberances and concave depressions blended together so as to form smoothly rounded peaks and valleys extending over substantially the entire working surface, said working surface comprising a metal sheet material affixed to said support member, said support member providing a substantially continuous planar surface for supportable contact with said metal sheet; and c. a multiplicity of abrasive particles fixedly positioned relative to said working surface so that at least portions thereof extend outwardly from the surfaces of the protuberances and depressions formed on said working surface.
 3. The abrasive member as defined in claim 2 in which said working surface is uniformly covered with a particle bonding material and said abrasive particles are embedded in said bonding material uniformly along the surfaces of the peaks and valleys of said working surface.
 4. The abrasive member as defined in claim 3 in which said metal sheet material is a soft, comparatively ductile metal which is wearable under operating conditions and said bonding material comprises a nickel coating uniformly covering said sheet material. 